A mail survey was conducted involving 102 hospital-based active hemodialysis (HD) centers in Saudi Arabia to assess the annual incidence of seroconversion of antibodies against the hepatitis C virus (HCV). Tests for anti-HCV, using second generation ELISA, were performed every three months on the study subjects for a period between January 1993 to December 1994. Response was received from 73 centers (72%) on 1,392 patients and from 61 centers (60%) on 694 staff members. Of the study patients, 733 (52.7%) were males, and 659 (47.3%), females; 1,093 (78.5%) were Saudis, while 299 (21.5%) were Non-Saudis. The mean age of the patients was 44.5 ± 14.3 years (range 10-75 years). The mean duration on HD was 3.1 + 2.1 years (range 3 months - 10 years). Reuse of the dialyzers was not practiced on any of the study patients. During the study period, 28% of the patients did not receive any blood transfusions while the remaining 72% received varying number of transfusions. The average prevalence of anti-HCV among HD patients was 70%,and among the dialysis staff was 1%. and the annual rate of serconversion was 7% to 9%. The anti-HCV seroconversion rate was significantly lower in the dialysis centers with more than 20 patients compared with the smaller dialysis centers (P< 0.0001). Also, there was a significant correlation between increased rates of seroconversion and duration on HD as well as with history of blood transfusions (P< 0.001). There were no significant differences in the rates of anti-HCV seroconversion related to the sex, age or nationality of the patients. There was no correlation between the elevation of liver enzymes or presence of HBV infection and the annual rate of seroconversion. We conclude that the annual incidence of the seroconversion of anti-HCV in the HD population in Saudi Arabia is 7-9% and isolation of the anti-HCV positive patients may help in decreasing this incidence.

How to cite this article:Souqiyyeh MZ, Shaheen FA, Huraib SO, Al-Khader AA. The Annual Incidence of Seroconversion of Antibodies to the Hepatitis C Virus in the Hemodialysis Population in Saudi Arabia. Saudi J Kidney Dis Transpl 1995;6:167-73

Hepatitis C Virus (HCV) infection is more frequent in patients on hemodialysis (HD) than in the general population [1],[2],[3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13],[14],[15] and is known to induce chronic liver disease[7],[8],[16],[17],[18] . There have been many reports about the prevalence of anti-HCV, rates of anti-HCV seroconversion and the associated risk factors among HD patients [6],[9],[19],[20],[21],[22],[23],[24],[25] . Varying prevalence rates of anti-HCV have been reported from various centers in Saudi Arabia [18],[26],[27],[28],[29] . However, there are no reports on the anti-HCV seroconversion rate from this country.

We report in this multi-center study, the prevalence of anti-HCV positivity and the annual seroconversion rates among the HD population in Saudi Arabia.

Patients and Methods

A mail survey was conducted involving 102 hospital-based active HD centers in Saudi Arabia for the period between January 1993 to December 1994. Anti-HCV antibody test was routinely performed every three months on the HD patients in each center. We received response to our questionnaire from 73 centers (72%), on 1,392 patients as well as from 61 centers (60%) involving 694 staff members. Thirty one centers (42.5%) had five or less patients, 14 centers (19.2%) had 5-10 patients, 13 centers (17.8%) had 10-20 patients, and 15 centers (20.5%) had more than 20 patients of which three centers had more than 150 patients each. There were 733 male patients (52.7%) and 659 (47.3%) female patients in the study group. One thousand and ninety three patients (78.5%) were Saudis, while 299 patients (21.5%) were Non-Saudis. The mean age of the patients was 44.5 + 14.3 years (range 10­75 years). The mean duration on HD was 3.1 + 2.1 years (range 3 months - 10 years). Reuse of dialyzers was not practiced on any of the study patients. During the study period, 28% of the patients did not receive any blood transfusions, 31% received 1-2 transfusions, 20% received 3-5 transfusions, and 21% received 5-10 transfusions. The sensitive second generation ELISA test [6],[7],[30],[31],[32],[33],[34] (Abbott kits produced by Abbott laboratories, USA or Sanafi Pasteure Kits produced by Pasteure Laboratories, France) which detects antibodies directed against both non-structural (c100 and c33) and structural (c22) HCV antigens was used. A correlation between positive anti-HCV by second generation ELISA and positive HCV-RNA by polymerase chain reaction and infectivity of the patients has been previously demonstrated[6],[7],[8] .

All the study patients were also tested for hepatitis B virus (HBV) status using ELISA, and liver enzymes including alanine aminotransferase (ALT) and aspartate aminotrans-ferase (AST). Raised enzymes was defined as an increase by at least one and a half times above the upper normal level.

Statistical analysis

The results in this study are reported as the mean ± SEM as indicated. Paired and unpaired Student's t-tests were used where indicated. P values < 0.05 were considered as significant.

Results

The prevalence of anti-HCV positivity and the rates of seroconversion according to the size of the dialysis centers are given in [Table - 1]. There were 751 patients (54%) who were anti-HCV positive since the start of the study (Group 1) and 427 patients (31%) who remained anti-HCV negative throughout the study period (Group 2). A total of 102 patients (7%) seroconverted to positive after one year (Group 3), 44 patients (3%), seroconverted after one and half years (Group 4) and 68 patients (5%), seroconverted after 21 months (Group 5) [Table - 1]. The overall prevalence of anti-HCV was 70%, and the annual incidence of anti-HCV seroconversion was 7% to 9%. This incidence of seroconversion was significantly lower in the dialysis centers with more than 20 patients compared with the smaller dialysis centers (P< 0.0001). There was no significant difference in the annual incidence of seroconversion among the smaller dialysis centers. Also, there were no significant differences in the the annual incidence of anti-HCV seroconversion and the sex, age or nationality of the patients.

There was a significant correlation between the annual incidence of the HCV seroconversion and the duration on HD, especially among patients who were on HD for two years or more [Table - 2].

A total of 698 of the 965 patients (72%) with positive anti-HCV antibodies had received varying number of transfusions. There was a significant positive correlation between history of blood transfusion and the incidence of seroconversion (P<0.001). However, there was no correlation between the incidence of seroconversion and the number of transfusions [Table - 3]. There was an elevation of AST levels in 60 (7.5%) and ALT levels in 113 (8.12%) of the anti-HCV positive patients. There was no correlation between the elevation of liver enzymes and the frequency of blood transfusions, the duration on HD or the annual rate of the incidence of seroconversion.

In the study group, 914 (65.7%) of the patients were HBV negative and HCV positive; 363 (26.1%) were HBV and HCV negative; 73 (5.2%) were HBV and HCV positive and 42 (3%) were HBV positive and HCV negative. The presence of HBV infection did not significantly affect the incidence of seroconversion.There were 11 staff members out of 694 persons screened from 61 hospitals who were positive for anti-HCV with a prevalence rate of 1%.

Discussion

The prevalence of anti-HCV antibodies in the HD population in Saudi Arabia has been reported to be between 11.4% [18] and 41.9% [35] , which is higher than the 6% [36] , and 12% prevalence rates reported from other countries [6] . In our study, we found a prevalence of 70%. The incidence of anti­HCV seroconversion was reported by some studies as 4.9% [37] , 1.7% [6] , 4.6% [20] , 2.2% [24] and 13.1% [25] . Our study estimated a slightly higher rate of seroconversion of between 7% to 9%. The incidence of anti-HCV seroconversion was significantly lower in the larger HD centers when compared with the smaller ones. One study reported an increased prevalence of the seroconversion among females on HD [1] , a finding that was not substantiated in another study [38] . We too, did not find any correlation between sex and the prevalence of anti-HCV or the annual incidence of seroconversion.

A higher incidence of anti-HCV seroconversion has been reported in the older age group [23] , though lack of such correlation also has been reported [38] . We did not find any correlation between either the prevalence of anti-HCV or the annual incidence of seroconversion and the age of the patients.

Numerous studies have found a correlation between the duration on HD and the prevalence of anti-HCV and the incidence of anti-HCV seroconversion [5],[6],[10],[13],[16],[20],[24],[26],[39],[40] . One study found it significant only with a duration on HD of more than five years [12] , while another found a correlation with duration more than three years [27] . Studies have also reported no correlation between anti-HCV prevalence with the duration on HD [41] . We found a significant correlation between the duration on HD and the prevalence of anti-HCV as well as annual incidence of seroconversion.

The issue regarding correlation between prevalence of anti-HCV and annual incidence of seroconversion with blood transfusions is controversial. Many studies have reported positive correlation [4],[6],[9],[10],[11],[12],[13],[14],[15],[16],[19],[20],[21],[22],[23],[38],[42],[43],[44],[45],[46],[­47], while some others have not found any [25],[39],[41],[48],[49],[50] . Some studies suggest that the prevalence of anti-HCV and seroconversion is higher in patients who have received transfusions of 5 to 50 units of blood [10],[27],[51] . Many of the studies could not explain all the cases of anti-HCV seroconversion on the basis of transfusion only and have suggested a nosocomial factor for seroconversion [4],[6],[7],[10],[13],[23],[47],[52],[53] . We found a correlation between the annual incidence of anti-HCV seroconversion and history of blood transfusion. However, seroconversion also occurred in 28% of patients who did not receive any transfusions. This is compatible with the previous reports of involvement of a possible nosocomial factor. Further, we did not find any correlation between the rate of annual incidence of seroconversion and the number of transfusions.

Some reports have found elevation of liver enzymes to be more prevalent in the anti-HCV seroconverted groups [1],[10],[12],[13],[22],[23],[26],[47],[54] , while others did not find such correlation [7],[25],[55] . In our study, we did not find any correlation between the prevalence of anti-HCV or the incidence of the seroconversion rate with the recent elevation of liver enzymes.

One study reported an increased prevalence of seroconversion in the HBV infected HD patients [12] . No such correlation was found in our study.

Several studies have reported the prevalence of anti-HCV seroconversion among the staff members of the dialysis centers as 1% [20],[56] , 2% [24] , 2.4% [57] , 8% [13] . We found only 1% prevalence of anti-HCV among staff members in the HD centers in Saudi Arabia, while the prevalence of anti-HCV in the general population in Saudi Arabia is reported to be 3.6% [27] .

In conclusion, we found the prevalence of anti-HCV in the HD population in Saudi Arabia to be 70% and among the staff members of the dialysis centers to be 1%. The annual incidence of seroconversion was 7-9% among the HD patients. There was no correlation with the age, sex and nationality of the patients, recent elevation of liver enzymes or the presence of HBV carrier status in these patients. There was a positive correlation between the incidence of seroconversion and the duration on HD and history of blood transfusions and an inverse correlation with the size of the dialysis unit. The positive correlation of anti-HCV positivity with the duration on HD coupled with a 28% positivity among patients who have never been transfused, point towards a nosocomial factor in the transmission of the virus and argues strongly in favor of isolating anti-HCV positive patients during dialysis sessions.

Acknowledgment

We would like to thank Mr. M.A. Taher and Mr. Pedly F. Atienza of SCOT for their valuable secretarial assistance in preparing the manuscript.